Getting it to bloom

Why won't my silver spike grass bloom? (and how to make it flower)

Also called silver spike grass, rough feather grass, spear grass, silver needle grass (Stipa calamagrostis).

More about silver spike grass

About silver spike grass

Stipa calamagrostis · also called silver spike grass, rough feather grass · flowering

Silver spike grass is a cool-season ornamental grass producing arching clumps of narrow blue-green foliage and showy, silver-green feathery plumes from midsummer that age to warm tawny tones and persist through winter. Drought-tolerant and low-maintenance, it excels in sunny, well-drained borders, gravel gardens, and water-wise plantings. RHS Award of Garden Merit holder.

Plant type: flowering

The reasons silver spike grass isn't blooming

Almost every non-blooming silver spike grass traces back to one of these, roughly in order of how common they are:

Too little sun — most of these need full sun (or very bright light) to flower well; shade gives leaves, not blooms.
Too much nitrogen feed, driving lush foliage at the expense of flowers (very common with general or lawn feeds).
The plant has not been deadheaded, so it stops flowering once it sets seed.
Irregular watering — drought or waterlogging at the budding stage makes buds abort.
It is still too young or was checked by a transplant and is rebuilding before flowering.

Feeding silver spike grass a high-nitrogen general feed and growing it in too little sun — you get a big leafy plant and almost no flowers.

The fix — how to get silver spike grass to flower

Maximise sun. Give silver spike grass the sunniest spot you have — for most bedding and fruiting plants, more direct light directly means more flowers.
Switch the feed. Move off high-nitrogen feeds and use a higher-potassium "bloom" or tomato-type feed as it comes into flower.
Deadhead regularly. Remove spent flowers often to keep it producing more rather than stopping to set seed.
Water consistently. Keep moisture even through budding and flowering — drought-then-flood swings make buds drop.

Light and feeding do most of the heavy lifting here. Dial in the spot with the light guide for silver spike grass and get the feeding right with the silver spike grass fertilising schedule — the wrong feed (too much nitrogen) is one of the most common silent reasons a healthy plant makes leaves instead of flowers.

Bloom season and what to expect

silver spike grass flowers across its growing season (mostly summer) and, kept fed and deadheaded, can bloom for many weeks or right up to frost.

Post-bloom care so it flowers again

Deadhead, keep feeding lightly, and many will rebloom; collect seed from the best plants at the end of the season if you want to grow them again.

For everything else this plant needs day to day, see the full silver spike grass care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

silver spike grass blooming — frequently asked questions

Why won't my silver spike grass flower?

silver spike grass blooms on the season's growth given enough sun, warmth and the right feed — there is no cold or photoperiod trick, just good growing conditions and a bloom-leaning feed. The most common reason it is not happening: Too little sun — most of these need full sun (or very bright light) to flower well; shade gives leaves, not blooms.

How do I make silver spike grass bloom?

Give silver spike grass the sunniest spot you have — for most bedding and fruiting plants, more direct light directly means more flowers. Move off high-nitrogen feeds and use a higher-potassium "bloom" or tomato-type feed as it comes into flower.

When does silver spike grass normally bloom?